The Preparation Of Quasi-IPN Of LPA And PDMA And Its Application In Separation Of Biomacromolecules

Capillary electrophoresis (CE), which shows high separation efficiencies, high resolution, rapid analysis time, ease of automation, and less sample and reagent consumption, has been accepted widely as a powerful analytical method for biomolecular separation.It is an effective way to achieve ideal separation results utilizing separation medium for analysis of biomolecules. However, separation medium which is particularly devised for the special separation purpose possesses its unique characteristics. During the separation and sequencing analysis of DNA by CE, the research of sieving matrices is very important because they determine the migration behavior, resolution, read length and reproducibility of DNA during separation. An ideal separation medium for DNA separation should possess the following properties: high sieving ability, dynamic coating ability, and relatively low viscosity. Among the polymers which have been researched, linear polyacrylamide (LPA) has high sieving capacity for DNA fragments. Unfortunately, LPA has no dynamic coating ability to prevent the adsorption of DNA on the capillary wall.While separating protein by CE, however, the electrostatic interaction between proteins, especially basic proteins, and the negatively charged capillary wall leads to peak tailing, band broadening, the adsorption of protein onto the capillary surface, or even their irreversible adsorption with loss of samples. The most common approach explored to minimize this adsorption has been to coat the capillary inner surface with polymer. Physical adsorbed coatings become more attractive due to their fast coating procedure and good reproducibility. Polymer such as poly (ethylene oxide) (PEO), poly (vinyl alcohol) (PVA), poly (N, N-dimethylacrylamide) (PDMA) and poly (N- hydroxyethylacrylamide) (PHEA) can function as stable"dynamic"capillary coatings, among which PDMA has the best self-coating ability.Since CE is a versatile means for analyzing biomolecules, it is very significant for a separation medium which is provided with multifunction quality and can be used for ssDNA sequencing, dsDNA separation, and protein analysis. Based on the above discussion, the separation medium for protein and DNA separation should possess both high sieving ability and self-coating ability. So we design work on the following aspects: 1. Silver nanoparticles (SNPs) were prepared and added into quasi- interpenetrating network of LPA (4.60 MDa) and PDMA to form polymer/metal composite sieving matrices. The sequencing performances on ssDNA using quasi-IPN and quasi-IPN/SNPs as sieving matrices were studied and compared by CE. The influences of the concentration of SNPs on the sequencing performances of ssDNA were also discussed.2. Quasi-IPN containing higher-molecular-mass LPA could not get good resolution on dsDNA separation. In this study, LPA with low molecular mass (<1.00 MDa) was synthesized using isopropanol as chain transfer agent to control the molecular mass of the product. This polymer was employed for the first time on the separation of dsDNA. The performance of quasi-IPN on dsDNA separation was determined by polymer concentration, electric field strength, LPA molecular masses and different AM to DMA ratio.3. Quasi-IPN combines the superior sieving ability of LPA with the coating ability of PDMA. In this study, the coating ability of quasi-IPN has also been investigated by serparating proteins. The coating ability of the polymer was investigated by separating basic proteins, neutral protein and acid proteins. Excellent results were obtained because quasi-IPN coatings effectively prevented the adsorption of protein and stabilized EOF. Quasi-IPN coatings were suitable for analysis of complicated proteins.